This invention generally relates to a valve for a pressurized aerosol container, which valve has a very limited vertical travel path to reach the full open position.
Aerosol containers are widely used to package a variety of fluid materials, both liquid and powdered particulate products. Typically, the product and a propellant are confined within the container, at above atmospheric pressure, and the product is released from the container by manually opening a dispensing valve to cause the pressure within the container to deliver the product through the valve and connecting conduits to a discharge orifice.
The dispensing valve, crimped to a mounting cup having a sealing gasket, is normally mounted in a top opening of the container, which opening is defined by a component commonly referred to as the xe2x80x9cbeadxe2x80x9d of the container opening. The mounting cup includes a central pedestal portion for holding the dispensing valve, a profile portion extending outward from the pedestal portion, which profile portion merges into an upwardly extending body portion, the body portion emerging into a hemispherically-shaped channel portion terminating in a skirt portion, which channel portion is configured to receive the bead portion of the container opening. The sealing gasket normally is disposed within the channel portion and in many gasket configurations extends downward along a part of the body portion. After the sealing gasket is disposed onto the mounting cup, the cup is positioned onto the container and the cup is clinched to the container. The clinching operation is well-known to those skilled in the aerosol container art.
The aerosol dispensing valve generally comprises a hollow valve stem having a wider base portion integral therewith, generally referred to as the valve stem body. Positioned intermediate the valve stem and valve stem body is a valve stem groove. A valve housing surrounds the valve stem body, and is crimped and held within the pedestal portion of the mounting cup. A spring is disposed between the bottom of the valve housing and the underside of the valve stem body, and, in many instances, a hollow tube (dip tube) extends from the outside base of the valve housing to the bottom of an associated aerosol container.
The valve stem groove has one or more opening(s) or orifice(s) extending through the valve stem groove wall and communicating with the conduit in the hollow valve stem. An annular valve sealing gasket with a central opening for receiving the valve stem is positioned in the annular valve stem groove, with the orifice(s) within the groove being positioned such that the gasket seals the orifice(s) when the valve is in the closed position. When the valve is opened by vertically depressing the valve stem, the valve stem moves axially downwardly from its closed position to cause the orifice(s) in the annular valve stem groove to move out of registry or sealing relation with the gasket. Product in the aerosol container then, under the influence of the pressure generated by the propellant, passes upwardly through the dip tube into the valve housing, then through the orifice(s) in the annular valve stem groove into the hollow valve stem, and outwardly through an outlet nozzle in an actuator button, cap or spout mounted atop the valve stem.
Heretofore, most commercial vertically-actuated aerosol valves have had a stroke path of 0.8 mm to 1.0 mm in order to achieve a full spray rate.
Recently, marketers of aerosol products, as well as consumers, have sought an aerosol package wherein the product is delivered from the container after a very short stroke. Both marketers and consumers equate a short valve opening stroke to easy actuation of the aerosol valve. Further, with prior aerosol valves, the actuation stroke could be monitored to partially open the valve through controlling the depression of the valve stem to less than full depression. Such partial depression of the valve stem prevents a full spray rate and often results in a spray that is undesirably coarse or dripping.
The applicant is aware of a commercial aerosol valve that has a short stroke in order to fully open the valve. The structure of this valve comprises a valve body having a centrally disposed hollowed-out portion in its top surface and a separately molded valve stem having orifice slots at its base, which valve stem extends into the valve body; the result being that the orifice slots sit beneath the sealing gasket disposed about the valve stem and atop the valve body. Depression of the valve stem immediately separates the underside of the gasket from the top surface of the valve body and the propellant/product within the container may pass through the space between the underside of the gasket and the top surface of the valve housing into the hollowed-out portion of the valve body and into the slots in the valve stem. One difficulty with the above-described aerosol valve is that it requires an assembly operation to combine the valve body and valve stem. Additionally, the above-described aerosol utilizes a straight shank stem. Straight shank stems are more difficult to properly seal with a surrounding gasket; said stems being prone to side spitting. Moreover, straight shank stems are prone to having the gasket drag above the valve stem orifice during the closing of the valve and, thus, closing slowly or not at all, particularly where, the product/propellant system in the aerosol container causes substantial swelling of the gasket.
An object of the invention is to provide an integral (one-piece) aerosol valve stem/valve body having a valve stem orifice sealed by a surrounding gasket, which valve is fully opened upon a relatively short vertical actuation stroke.
The improved aerosol valve of this invention comprises a gasketed integral valve stem and valve body wherein the stem orifice is disposed at the portion of the valve stem adjacent the upper surface of the valve body in a gasket-receiving groove that has an arcuate lower portion and an upper tapered shoulder portion.